1261640272 has 20 divisors (see below), whose sum is σ = 2446583860. Its totient is φ = 630263808.

The previous prime is 1261640269. The next prime is 1261640309. The reversal of 1261640272 is 2720461621.

It can be written as a sum of positive squares in 2 ways, for example, as 1011494416 + 250145856 = 31804^2 + 15816^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15747 + ... + 52642.

It is an arithmetic number, because the mean of its divisors is an integer number (122329193).

Almost surely, 2^1261640272 is an apocalyptic number.

It is an amenable number.

1261640272 is a deficient number, since it is larger than the sum of its proper divisors (1184943588).

1261640272 is a wasteful number, since it uses less digits than its factorization.

1261640272 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69550 (or 69544 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 1261640272 is about 35519.5758983691. The cubic root of 1261640272 is about 1080.5507798787.

The spelling of 1261640272 in words is "one billion, two hundred sixty-one million, six hundred forty thousand, two hundred seventy-two".